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| author | Wim Van Sebroeck <wim@iguana.be> | 2011-07-22 22:59:17 +0400 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@iguana.be> | 2011-07-28 12:01:14 +0400 |
| commit | 7e192b9c4234d29bdc20ac8d0a67edf7624b4206 (patch) | |
| tree | d46f8208ce67391166e8fbdcc3fe92e6ee01ea3c /drivers/watchdog/watchdog_dev.c | |
| parent | 017cf0805105496ab1880e236cb3e4bf156fb915 (diff) | |
| download | linux-7e192b9c4234d29bdc20ac8d0a67edf7624b4206.tar.xz | |
watchdog: WatchDog Timer Driver Core - Add nowayout feature
Add support for the nowayout feature to the
WatchDog Timer Driver Core framework.
This feature prevents the watchdog timer from being
stopped.
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'drivers/watchdog/watchdog_dev.c')
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index db40c6c79ef8..ac20f92347b1 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -98,11 +98,18 @@ static int watchdog_start(struct watchdog_device *wddev) * Stop the watchdog if it is still active and unmark it active. * This function returns zero on success or a negative errno code for * failure. + * If the 'nowayout' feature was set, the watchdog cannot be stopped. */ static int watchdog_stop(struct watchdog_device *wddev) { - int err; + int err = -EBUSY; + + if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { + pr_info("%s: nowayout prevents watchdog to be stopped!\n", + wdd->info->identity); + return err; + } if (test_bit(WDOG_ACTIVE, &wdd->status)) { err = wddev->ops->stop(wddev); @@ -123,7 +130,7 @@ static int watchdog_stop(struct watchdog_device *wddev) * * A write to a watchdog device is defined as a keepalive ping. * Writing the magic 'V' sequence allows the next close to turn - * off the watchdog. + * off the watchdog (if 'nowayout' is not set). */ static ssize_t watchdog_write(struct file *file, const char __user *data, @@ -271,8 +278,8 @@ out: * @file: file handle to device * * This is the code for when /dev/watchdog gets closed. We will only - * stop the watchdog when we have received the magic char, else the - * watchdog will keep running. + * stop the watchdog when we have received the magic char (and nowayout + * was not set), else the watchdog will keep running. */ static int watchdog_release(struct inode *inode, struct file *file) @@ -281,7 +288,8 @@ static int watchdog_release(struct inode *inode, struct file *file) /* * We only stop the watchdog if we received the magic character - * or if WDIOF_MAGICCLOSE is not set + * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then + * watchdog_stop will fail. */ if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) || !(wdd->info->options & WDIOF_MAGICCLOSE)) |